Four of the Papst 8412N/GL case fans (rated the quietest, by far, in my 2-in/2-out combination).
Perhaps two more for the CPUs, if the PSU I get has enough 4-pin connectors for all of them plus my 3-4 drives.
Two Thermalright SLK800 heatsinks, if I can find somewhere that sells them.
Striving for greatness 